Wheel adhesion control for railway rolling stock



Gd. 9, 1956 HUDSON 2,76%,Q56

WHEEL ADHESION. CONTROL FOR RAILWAY ROLLING STOCK Filed Nov. 5, 1951 2 Sheets-Sheet l INVENTOR. fowl/VB. Hausa/v,

Oct. 9, 1956 E. B. HUDSON 2756,@56

WHEEL ADHESION CONTROL FOR RAILWAY ROLLING STOCK Filed NOV. 3, 1951 2 Sheets-Sheet 2 e. C Excl TH T/ON Chan/15f 1 1V V EN TOR. Zw/N .5 Hausa/v,

ATTORNEYS- nited States area:

WHEEL ADHESION CONTROL FOR RAILWAY ROLLING STOCK Edwin B. Hudson, Middletown, Ohio Application November 3, 1951, Serial No. 254,696 9 Claims. (Cl. 291-2) This invention relates to wheel adhesion control for railway rolling stock including locomotives and cars.

Rail condition Zero to 20 M. P. H.

to the rails, and particularly when the sliding is in the early stages. The table below shows the ooeflicient of friction for a series of slip velocities, and it shows quite clearly that the coefficient of friction drops off very rapidly with the amount of slip.

Feet per Second Miles Per Coeflicient Hour of Friction R It is therefore an object of the present invention to apply the abrasives to the rail at the point when is the object of providing sensing means to sense the moment when slipping begins.

A great deal of effort has been expended by inventors to improve the braking capacity on high-speed trains by means of clasp brakes and by the introduction of off wheel braking by the use of brake drums. It has also been proposed to combine conventional brake shoe braking with off wheel braking. But this approach to the problem has shown little promise because wheel adhesion to the rail is still the dominant problem.

Ever since the earlier stages of the railroads there has been no means for improving wheel adhesion, except an abrasive such as sand applied between the wheel and the I 2,766,056 Patented Oct. 9, 1956 rail. At the present time sand is used only on the locomotive for improving traction and braking, and it has not been used on the cars of a train to prevent wheel sliding. With the advent of high-speed trains this has now become necessary.

momentarily releasing the began by means of an automatic dethat there is no braking effect most needed. This approach, therefore, is a negative approach to the solution of the braking problem because the stopping distance is greatly increased, and in an emergency situation can be the cause of fatal accidents.

Similarly, the problem of forward Wheel slip under driving conditions has been approached negatively. Various inventors have suggested automatic means for reducing the applied power when forward slip of the driving wheels occurs. This, of course, reduces the tractive effort of the locomotive, and when such reduction of tractive effort occurs on an up grade the problem is not solved because at such time all available power is required. Under such conditions of reduction of the use of available power the effectiveness of the locomotive is reduced since it is unable to deliver the performance for which it was designed.

It is another object of my invention therfore to depart from the solutions suggested in the prior art by increasing rail adhesion automatically. It is an object of my invention to stop the unfavorable sliding conditions in their incipient stages so as to in effect, gear the train to the rail and insure safer operation and more effective use of the equipment.

Excessive use of sand on railroad rails is undesirable for the reason that it may short out the block signal system, and therefore, it is desirable to use a minimum amount of sand. It is therefore yet another object of my invention to provide a device whereby the minimum amount of sand will be used since the sand will be automatically applied at the instant that wheel slipping begins whereby slippage will be stopped with a minimum use of sand. Furthermore, an object of the invention is to provide a device whereby sand will not beapplied to the rail when no slippage is occurring.

While braking slippage has been a severe problem for many years, the problem of driving slip or forward slip has not become serious until the introduction of the diesel locomotive which has high torque capacity driving motors on the driving axles. Tests have been made by tape recording devices to ShOW that the driver wheels on such diesel locomotives often have a forward slip which greatly exceeds the train velocity. In one particular test the wheel velocity was 6.67 times the train velocity. In other tests on a train running miles per hour, the wheels were forward slipping at miles per hour. Such tremendous differences in wheel and train velocities not only reduce the tractive efficiency of the locomotive, but often cause serious damage to the motors and gears. When the wheels stop slipping as a result of improved rail surface conditions, the cessation of slippage occurs with great suddenness and tremendous forces of deceleration are transmitted to the traction motors and gears, often requiring complete replacement of these parts as a result of the damage caused to them.

A principal object of my invention therefore is, to provide automatic means to apply sand to the rail, based on a speed'comparison of two axles. On locomotives the speed comparison is made between a power driven axle and an idle axle. On cars having all idle axles the control will operate on the basis of a speed comparison between a normally braked axle and a slightly overbrahed axle. The over-braked axle will slow down faster than the normally braked axle thereby producing the sensing required for the operation of my invention.

It is a still further object of my invention to provide a constant speed comparison as long as the train is in motion, and to provide the comparison completely automatically and to provide for automatic sanding so that no attention whatever is required from the engineer. With my invention there will be no need for a sanding control valve in the engine cab. 1

It is a still further object of my invention to apply sand in proportion to the amount of wheel slip, whereby the sand requirements are reduced since wheelslip will be controlled at the first indication'by the immediate application of a small amount of sand. As soon as the slip has been controlled the amount of sand supplied will be reduced until the slip is entirely stopped, whereupon the application of sand will be stopped.

It is a further object of the invention to provide a device as above outlined which will be relatively inexpensive and which will greatly increase the safety of train operation, and which will greatly reduce the damage to wheels, traction motors andgears.

These and other objects of the invention which will become apparent to those skilled in the art upon reading these specifications, or which may be pointed out ingreater detail hereinafter, I accomplish by that certain construction and arrangement of parts of which I shall now describe certain exemplary embodiments.

Reference is made to the drawings forming a part hereof, and in which:

Figure 1 is a plan view of a three-axle truck, having two driver axles and one idle axle wherein the speed comparison is made by an electrical differential means;

Figure 2 is a fragmentary view similar to Figure 1 where the speed comparison is made by means of a mechanical differential;

Figure 3 is an elevational view of a truck according to Figure 1;

Figure 4 is a fragmentary end elevational view of a truck as seen from the right of Figure 3;

Figure 5 is a fragmentary view partly in elevation and partly in cross section of a star type feed valve for sand;

Figure 6 is a side elevation of Figure 5, with parts broken away to show the construction;

Figure 7 is a typical wiring diagram trical differential is used according to Figure 1;

Figure 8 shows a typical A. Cwiring diagram using a mechanical differential according to Figure 2; and

Figure 9 shows a typical D. C. wiring diagram using a mechanical differential according to Figure 2.

Briefly in the practice of my invention I provide a differential which may be either a mechanical differential or an electrical differential, and -I feed into the two inputs of the differential data proportional to the speeds of two different wheels. In the case of a locomotive, one of the wheels will be a driver wheel and the other will be an idler wheel; in the case of a railway car, one of the wheels will be a normally braked wheel and the other will be an over-braked wheel.

The differential output will then be proportional to the amount of slippage, or in other words, it will be proportional to the relative speeds of the two inputs.

I provide a source of supply of sand with a tube or pipe to convey the sand to the rail adjacent a wheel, and in the tube or pipe I provide a valve which may be of the star type which will cause sand to be fed to the rail whenever the valve is rotating. I then drive this valve from the output of the differential. This may be accomplished either by the so-called D. C. step-by-step system, or by the well-known selsyn system, or by any other desired means.

wherein an elec- In order to simplify the drawings the main frames and brakes have been omitted and only the principal rotating parts have been shown. In Figure l, I have shown an exemplary truck having three axles indicated at A, B, and C. Axles A and C are driven by traction motors 1 through pinions 2 and gears 3. The axle B is idle, and of course will have no tendency to slip with respect to the rail. The axles A, B and C carry the conventional wheels 4.

Sand 5 is stored in containers 6 and is fed from the containers 6 to the rail 26 by a conduit 8. In the conduit 8, I provide a valve 7. The valve which I prefer to employ is shown in detail in Figures 5 and 6 and is of the star type so that it will feed sand only when it is rotating, and in an amount which is proportional to the rotation whether the rotation be clockwise or counterclockwise. This valve, as seen in Figures 5 and 6, has a rotor *1 mounted on a shaft 10 of a receiver 11. The other end of the shaft is supported by a bearing '7' in the cover 7". The receiver 11 is fastened to the valve body 7, as clearly shown in Figure 5. Whenever the receiver 11 is receiving impulses the rotor 9 is caused to turn and sand is fed to the rails.

It will be understood that there will be a sanding apparatus for a number of wheels, and that each of these will be provided with the machanism just described. The receivers of all of the sanding mechanisms may receive data from a common transmitter. The transmitter is indicated in Figures 2, 7, 8 and 9 at 12, and the transmitter 12 receives data from the output of a differential which may be an electrical differential as indicated at 14 in Figure 7 or a mechanical-differential as indicated at 17 in Figures 2, 8 and 9. In any event when the output of the differential rotates, which occurs whenever there is slippage, this rotation is imparted to the transmitter 12, and by it, is transmitted to one or more receivers 11 to actuate one or more rotors 9 in the valve 7. It will be clear that the faster the diiferential output rotates, the faster the rotors 9 will rotate and the more sand will be applied. It will also be clear that when there is no slippage the output of the differential will be stationary and the valve 7 will not deliver sand because the rotor 9 will be stationary.

In Figures 8 and 9 are shown circuits for the selsyn type of transmission (Figure 8) and the D. C step-bystep system (Figure 9). Since these systems are well known it is not thought tobe necessary to describe them further.

In the case of an electrical differential, as seen in Figures 1 and 7, a selsyn transmitter 15 is driven by the idle axle B, and a selsyn transmitter 16 is driven by a driver axle C. The transmitters 15 and 16 cause the receiver 14 to rotate in proportion to the difference in speeds between the transmitters 15 and 16, and therefore of the axles B and C. The device 141s what'is known as an electrical dilferential and is available on the open market. The circuits for it will therefore not bedescribed since they are well known and published. The output shaft of the electrical differential is indicated at 13 and this shaft drives the selsyn transmitter 12 as described above, and in response to movement of the selsyn'transmitter 12 the various selsyn receivers 11 will function.

In Figure 2 the axles B and C respectively drive shafts 21 and 25. The shaft 21 through the gearing 19, 20 drives an input shaft 18 of the differential 17, and the shaft 25 through the gearing 23, 24 drives the input shaft 22 of the differential 17. The differential 17 is in this instance a mechanical differential and is provided with the output shaft 13. The output shaft 13 drives a selsyn transmitterlZ which transmits data to the various receivers 11, either by the system of Figure 8 with A. C. or the system of Figure 9 with D. C. Again it will beclear thatithe shaft 13, which'is the output of the mechanical differential :17, rotates in proportion to the difference in speeds betweenthe axles B and C, and;d oes not rotate unless there is a difference between the speeds of these axles. As a matter of preference, the arrangement of Figure 7 is the most desirable because there is no mechanical differential mounted on the truck frame. The data is transmitted from the axles B and C to an electrical differential which may be mounted at a remote point within the car or locomotive.

It will be clear that the transmitter 12 will be proportioned to drive as many receivers 11 as required to provide sanding devices for two trucks, so that only one differential unit will be required for each car or locomotive unit.

It will be understood therefore that numerous modifications may be made without departing from the spirit of my invention, and that broadly speaking the term differential device as used in the claims will be considered to include both mechanical and electrical differential devices, and that an electrical rotation transmitter will be considered to include a selsyn transmitter or a D. C. stepby-step transmitter.

Other minor modifications may be made without departing from the spirit of the invention, and I therefore do not intend to limit myself other than as set forth in the claims which follow.

Having now fully described my invention What I claim as new and desire to secure by Letters Patent is:

1. A wheel adhesion control structure for railway rolling stock having at least two axles, comprising a differential device of the character having two input shafts and an output shaft and wherein the speed of rotation of said output shaft is proportional to the difference in rotational speeds of said input shafts, a driving connection from an axle of said rolling stock to one of said input shafts, a driving connection from a different axle of said rolling stock to the other of said input shafts, a supply of sand and means for conveying said sand to the track adjacent a wheel, rotatable feeding means for causing sand to be fed through said conveying means, and a driving connection between said output shaft and said feeding means.

2. The structure of claim 1 wherein one of said two axles is an idler and the other is a driver.

3. The structure of claim 1, wherein both of said axles are idlers, and wherein one of said axles is normally braked and the other is braked to a different degree.

4. A wheel adhesion control structure for railway rolling stock having at least two axles, comprising a mechanical differential of the character having two input shafts and an output shaft and wherein the speed of rotation of said output shaft is proportional to the difference input shafts, a driving connection from a different axle of said rolling stock to the other of said input shafts, a supply of sand and means for conveying said sand to the track adjacent a ing sand said output shaft and transmitter, an electrical rotation receiver electrically connected to said transmitter, and a driving connection between said receiver and said feeding means.

5. The structure of claim 4 wherein one of said two axles is an idler and the other is a driver.

of claim 4 wherein both of said axles are idlers, and wherein one of said ax a wheel, fed through said conveying means, a third electrical rotation receiver electrically connected to said transmitter, and a driving connection between said third receiver and said feeding means.

8. The structure of claim 7 wherein one of said two axles is an idler and the other is a driver.

9. The structure of claim 7, wherein both of said axles are idlers, and wherein one of said axles is normally braked and the other is braked to a different degree.

References Cited in the file of this patent UNITED STATES PATENTS 

